使用js写个方法截取视频的第一帧

"```javascript function captureFirstFrame(videoUrl, callback) { const video = document.createElement('video'); video.onloadeddata = function() { const canvas = document.createElement('canvas'); canvas.width = video.videoWidth; canvas.height = video.videoHeight; const ctx = canvas.getContext('2d'); ctx.drawImage(video, 0, 0, canvas.width, canvas.height); const dataURL = canvas.toDataURL('image/png'); callback(dataURL); }; video.src = videoUrl; }

// Example usage const videoUrl = 'www.example.com/sample.mp4'; captureFirstFrame(videoUrl, function(firstFrameData) { console.log('First frame captured:', firstFrameData); });